Code on Noise Levels on Board Ships. Noise by Mr... · 2011-12-05 · Code on Noise Levels on Board Ships - Key issues on revision of the Code - Kunihiko KITABAYASHI 1 @ 5th ASEF

Code on Noise Levels on Board Ships

- Key issues on revision of the Code -

Kunihiko KITABAYASHI

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@ 5th ASEF Meeting at Busan, 1 &2 December 2011

Revision of “the IMCO Noise Code” has been discussed at IMO DE Sub-Committee and it would be mandatory under SOLAS. In this presentation, outline of the draft revised Code with some key issues in which ASEF members might be interested are introduced.

Introduction

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1. Revision of the Noise Code 2. Draft revised Code & key issues 3. Possible time schedule 4. Conclusion

Contents

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1. Revision of the Noise Code

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1. Revision of the Noise Code (1)

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“IMCO Code on Noise Levels on Board Ships” (hereinafter “Noise Code”) was adopted in 1981 as IMCO Assembly Resolution A.468(XII)

The Code is a recommendatory rule and referred at footnote of SOLAS II-1/36 (machinery)

Status of the Code


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The Code states: “…Noting that high noise levels on board ships could affect seafarers’ health and impair the safety of the ship,…”

The aim of the Code


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The current Code mainly stipulates:

Maximum sound pressure levels for each space Noise exposure limits *

Acoustics insulation b/w accommodation spaces Ear protection

* Noise exposure represents the equivalent noise exposure level for given time duration. (ex. 24 hours)


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MSC83 (Oct. 2007) -decided to revise the Code DE53 (Feb. 2010) -Proposal of revision to the current Code was submitted Enhancement of max. noise level by 5dB for each space

Discussed at DE54 (Oct. 2010) , DE55 (Mar. 2011) and CG - CG Report has been submitted to DE 56

DE 56 (Feb. 2012) -Revision work would be finalized

Course of discussion at IMO

2. Draft Revised Code and key issues

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2. Draft revised Code and key issues (1)

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Keep the basic structure of the current Code Reflect the latest technology and related ISO/IEC Distinguish into mandatory/recommendatory parts Cover design/sea trial stage

Basic concepts of revision work:


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General (Chapter 1) Measuring equipment (Chapter 2) Measurement (Chapter 3) Maximum acceptable sound pressure level (Chapter 4) Noise exposure limit (Chapter 5) Acoustic insulation b/w accommodation spaces (Chapter 6) Hearing protection and warning information (Chapter 7) Appendices There are key issues other than maximum noise level which related parties should notice.

Structure of the draft revised code


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Scope: (from 1.1.1 of draft revised Code) “…The Code is intended to provide the basis for a design standard, with compliance based on the satisfactory conclusion of sea trials that result in issuance of a Noise Survey Report. Ongoing operational compliance is predicted on the crew being trained in the principles of personal protection and maintenance of mitigation measures. These would be enforced under the dynamic processes and practices put in place under SOLAS Chapter IX (ISM Code).”

Chapter 1: General


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Mandatory in general, some parts recommendatory

Application: new ships of 1,600GT and greater

Exceptions: dynamically supported craft, high- speed craft, MODU, etc.

Chapter 1: General


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Sound level meters should be manufactured to conform to IEC 61672-1 (2005) Type/Class 1 (Former “precision grade sound level meters”) Calibration in accordance with IEC 60942-1:2003

Chapter 2: Measuring equipment

騒音計の写真


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Measurement should be conducted on completion of the construction of the ship Measurement method is based on ISO 2923:1996

A-weighted equivalent continuous sound level LAeq(T)

Chapter 3: Measurement


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At normal service speed and no less than [80][75]% of the MCR

Noise prediction is a recommendatory method

[Noise exposure level is also to be calculated for expected condition based on ISO 9612:2009] (discussion not completed)

Chapter 3: Measurement


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Chapter 4: Maximum acceptable sound pressure levels

Noise level limits (dB(A)) for each space

Designation of rooms and spaces Draft revised code

Current 1,600-10,000GT 10,000GT -

4.2.1 Work spaces

Machinery spaces (continuously manned) - - 90

Machinery spaces (not continuously manned) - - 110

Machinery spaces 110 110 -

Machinery control rooms 75 75 75

Workshops 85 85 85

Non-specified work spaces (other work areas) 85 85 90

10,000GT threshold was introduced by Japan’s proposal at DE54


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Noise level limits (dB(A)) for each space (continued)


Current 1,600-10,000GT 10,000GT -

4.2.2 Navigation spaces

Navigation bridge and chartrooms 65 65 65

Listening post, incl. navigating bridge wings

and windows

70 70 70

Radio rooms (with radio equipment operating

but not producing audio signals)

60 60 60

Radar rooms 65 65 65

4.2.3 Accommodation spaces

Cabin and hospitals 60 55 60

Mess rooms 65 60 65

Recreation rooms 65 60 65

Open recreation areas (external recreation

areas)

75 75 75

Offices 65 60 65

Differentiated noise levels for acc. spaces Introduced by Japan’s proposal at DE 54



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Noise level limits (dB(A)) for each space (continued)


Current 1,600-10,000GT 10,000GT -

4.2.4 Service spaces

Galleys, without food processing equipment

operating

75 75 75

Serveries and pantries 75 75 75

4.2.5 Normally unoccupied spaces

Spaces not specified 90 90 90



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A noise survey report should be made for each ship The format for the noise survey report is provided in appendix 1 The noise survey report should always be carried

on board ship



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Chapter 5: Noise exposure limits Seafarers should not be exposed to an “Lex,24h” exceeding 80dB(A)

“Lex,24h” represents the equivalent noise exposure level for a period of 24 hrs.

In spaces with sound pressure levels exceeding 85dB(A),

suitable hearing protection such as ear muff required

At construction stage, the actual noise exposure level cannot be determined. Only estimation can be done. After delivery, compliance with the noise exposure limits attributes to actual operation.


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Chapter 5: Noise exposure limits

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80

90

100

110

120

130

1 2 4 8 16

Noise

level,

dB(A)

Duration of exposure, hours

Nis

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L ex(24) = 105 dB(A)

L ex(24) = 80 dB(A)

No protection required

Zone E

No exposure - Zone A

Occasional exposure - Zone C,

Occasional exposure

Zone B,

Daily exposure - Zone D


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Chapter 6: Acoustic insulation between accommodation spaces

Objective: In order to make rest and recreation possible even if activities are going on in adjacent spaces


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Draft revision Current

Cabin to cabin Rw=35 Rw=30

Messrooms, recreation rooms, public spaces

and entertainment areas to cabins and

hospitals

Rw=45 Rw=45

Corridor to cabin Rw=30 -

Cabin to cabin communicating door Rw=30 -

Sound insulation index (Rw) according to ISO 717-1(1996) and ISO 10140-2(2010)


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The requirement for apparent weighted sound insulation index (R’w) in accordance with ISO 140-4 is also described in the draft revised Code |R’w – Rw| to be with tolerance of up to 3dB

It has not been decided whether R’w should be mandatory or recommendatory ・・・It is not easy to apply ISO 140-4 to ship structure


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Chapter 7: Hearing protection and warning information

Hearing protectors needed if sound pressure level is above 85 dB(A) In that case, C-weighted peak sound level should also be measured in order to determine the suitable hearing protectors Instruction for seafarers…may be recommendatory


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Chapter 7: Hearing protection and warning information

Selection of suitable hearing protectors should be in accordance with “HML Method” in ISO 4869-2 :1994 (Details in appendix 2) …The opinions were split whether it should be mandatory or recommendatory Warning notices for high level noise area (>85dB(A)) …Symbols to be developed ??


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Appendix 1: Format for noise survey report

Ship particulars, machinery particulars, measurement conditions, measured data, etc. should be recorded in the designated format and

be kept on board.


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Appendix 2: Guidance on inclusion of noise issues in Safety Management Systems (SMS)

Instruction to /Responsibility of seafarers Responsibility of ship operators

Selection of hearing protectors …HML method based on ISO 4869-2

This appendix may be recommendatory


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Appendix 3: Suggested methods of attenuating noise

Informative appendix for ship design, including noise prediction at design stage


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Appendix 4: Simplified procedure for determining noise exposure

Based on ISO 9612, a simplified method of calculation of expected noise exposure level after delivery is provided.

Obviously, actual noise exposure level fully

depends on the actual operation Whether this appendix to be mandatory or

recommendatory not discussed yet


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List of relevant ISO/IEC standards (not exhaustive)-1

ISO 2923:1996 Acoustics – Measurement of noise on board vessels ISO 1999:1990 Acoustics – Determination of occupational noise exposure and estimation of noise-induced hearing impairment

ISO 9612:2009 Acoustics – Determination of occupational noise exposure –Engineering method

ISO/IEC 17025:2005 General requirements for the competence of testing an calibration laboratories

IEC 61672-1:2002 Electroacoustics – Sound level meters


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List of relevant ISO/IEC standards (not exhaustive)-2

ISO 717-1:1996 Acoustics – Rating of sound insulation in buildings and of building elements – Part 1: Airborne sound insulation

ISO 140-3:1995 Acoustics – Measurement of sound insulation in buildings and building elements – Part 3: Laboratory measurement of airborne sound insulation of building elements

ISO 140-4:1998 Acoustics – Measurement of sound insulation in buildings and building elements – Part 4: Field measurements of airborne sound insulation between rooms

ISO 10140-2:2010 Acoustics – Laboratory measurement of sound insulation of building elements – Part 2: Measurement of airborne sound insulation

3. Possible time schedule

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3. Possible time schedule

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IMO/DE56 (Feb. 2012) is expected to finalize the work on revision of the Code

In the earliest case, MSC 91 (Nov. 2012) may adopt the relevant resolution(s) and new rule would be entered into force from July 2014

It depends on the discussion at DE and MSC

4. Conclusion

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4. Conclusion

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IMCO Noise Code revision work is in the final stage

There are other key issues than maximum noise level in the Code (ex. noise exposure, sound insulation…)

The Code contains regulations relevant to not only shipbuilders but also operators/seafarers

It is important for ASEF members to be familiar with

relevant ISO/IEC, and follow the discussion at IMO

Thank you for your attention !

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Code on Noise Levels on Board Ships. Noise by Mr... · 2011-12-05 · Code on Noise Levels on Board Ships - Key issues on revision of the Code - Kunihiko KITABAYASHI 1 @ 5th ASEF